A prank was pulled on a crowd waiting to see The Force Awakens (which was itself a mean joke IMHO, ahem) and onscreen all these fake spoilers got posted as answers to trivia questions that if true would have ruined the movie. Great collective reactions!
https://www.youtube.com/watch?v=DS_1vjOeEq4 (https://www.youtube.com/watch?v=DS_1vjOeEq4)